1. Field of the Invention
This invention relates to flight vehicles, especially flight vehicles requiring bi-directional, rotary movement translated to their movable members.
2. Description of Prior Art
Heretofore flight vehicle mechanisms designed to activate movable surfaces or systems were not simply designed, having one moving part with bi-directional capability. Consistent with a complex or hand powered activation mechanisms came many comprises not desired in flight vehicles.
Example 1 is an aircraft having retractable landing gear disclosed in U.S. Pat. No. 2,272,522 issued on Feb 10, 1942 to Mr. Hojnowski. The operation of the Hojnowski retractable landing gear system is based upon manually operated crank handles (2 men required) transferring force for retraction/extension via beveled gears on fixed shafts, worm wheels and worm shafts. This system has many disadvantages, namely:
1. it does not have one moving part, but several
2. power is provided by crewmen
3. it is impractical in aircraft requiring:
A. rapid or emergency operation of landing gear PA1 B. in aircraft with large or multiple retractable landing gear PA1 C. retractable landing gear systems to be housed in a small area or in the wing only PA1 D. no crew on board PA1 A. greater expense to manufacture, own, repair, replace PA1 B. lower useful life, less reliability, more easily subject to breakage PA1 C. not designed to move heavy loads PA1 A. exotic building materials are not required PA1 B. it can be simply designed for all types of aircraft PA1 C. the parts are easy to produce--die, die cast, molded, machined PA1 D. less tooling is required PA1 E. fewer man and machine hours required to manufacture and assemble PA1 F. there are few rigid tolerances PA1 G. it is easy to install PA1 H. it will be easy to inspect PA1 I. it will be simple to maintain PA1 J. it will be easy to trouble shoot or repair PA1 K. it will be easy to replace PA1 L. it will reduce aircraft cost of operation PA1 M. it can be the state of the art for years to come.
4. in an age where fuelburn and aircraft weight are critical, this system is much too heavy, slow and cumbersome
5. it is most impractical and in some instances impossible to activate any of the following flight vehicle movable members that said Rotary Cylinder Displacement Mechanism can activate, namely: ailerons, cannards, elevators, flaps, flaperons, flight guidance fins (missile), fully articulating horizontal stabilizer, helicopter blade activating devices, passenger doors, movable fuel flow and air induction systems, rudders, ground steering units, slats , slots, spoilers, speed brakes, thrust reversers, variable geometry wings, vectored thrust units to name many but perhaps not all.
Example 2 is a pressure operated retractable landing gear system, U.S. Pat. No. 3,739,519 issued June 19, 1973 to Garabello et al. It operates by pressure supplied to a piston which moves a piston rod which translates motion to landing gear through a series of collars, links, fastener pins, pivot pins and blocks. This system has many disadvantages and non applications, namely:
1. it is not adaptive or practical as a power source for those flight vehicle movable members listed in Section 5 of Example 1
2. it is not adaptive or practical in aircraft other than model aircraft
3. it has a multiple of moving parts which translates to:
4. this linkage, push/pull retraction system does not provide optimum leverage exerted through all degrees of radius of motion. Because of this design weakness, a heavier and larger system is now manufactured
5. if this system could be adapted to larger aircraft a piston rod wiper system would be required
6. as designed, one gear retraction system is required for each retractable landing gear
7. as designed, this mechanism does not produce more than about 90.degree. of movement.
Example 3 is a displacement mechanism disclosed in U.S. Pat. No. 4,398,682 issued on Aug. 16, 1983 to Mr. Bithrey. Fluid pressure operates a two part system separated by valves. In the first segment, pressure is introduced through ducts venting from two movable vanes into two cambers. Pressure in the chambers cause radial movement along the axis of the motor. The housing of the motor rotates approximately 90.degree. to position the attached fin perpendicular to the missile surface. An alternate set of chambers, flanges and valves located in the forward section of the displacement mechanism provide locking. The disadvantages to this system are:
1. it is a one way system, it is not bi-directional and, therefore, cannot by itself cycle landing gear or any of the movable members outlined in Section 5 of Example 1
2. the displacement mechanism is complex, difficult to manufacture and, therefore, expensive
3. it requires extremely high pressure to operate (10,000 psi recommended)
4. this design does not translate rotory motion through the shaft and or the housing, but just the housing
5. this design cannot translate more than 180.degree. of rotation.
Most users, therefore, would find it desirable to have a one moving part bi-directional rotary mechanism that is versatile, simple, rugged, reliable, inexpensive, light weight and safe.